Study Guide — Unit 1
Textbook material that will be covered on the exam: Chapt. 1 & 2 (see syllabus for specific pages), and Chapt. 3, pp. 109-130.
1. What are some physical and behavioral consequences of removing the testes (castration) of a person before they have reached puberty? Do these effects reflect organizational or activational effects of gonadal steroids?
2. What are some physical and behavioral consequences of removing the testes (castration) of a person after they have reached puberty? Do these effects reflect organizational or activational effects of gonadal steroids?
3. What are some physical and behavioral consequences of castration of an immature male chicken?
4. In A. A. Berthold's experiments, why did re-implantation of a testis into the abdominal cavity of a castrated chicken allow the chicken to develop into a "normal" rooster, even though no neural connection was established with the implanted testis?
5. Why did the single testis implanted into the chicken's abdominal cavity grow to be twice as large as a normal testis (i.e. what is the mechanism of compensatory hypertrophy)?
6. The report in the journal, Nature, from an individual who claimed that his beard grew more rapidly in response to anticipation of sexual activity is often cited as an example of behavioral circumstances influencing hormone secretion. What is one brain region that you would predict is involved in mediating the effects of this sexual anticipation on beard growth? Why? [hint: think about whether testosterone is part of a first, second or third order neuroendocrine circuit]
Methods for Studying Hormone—Behavior Interactions
1. What is "extirpation" and why is it a useful method for studying the effects of hormones on the body?
2. Why is it often important to include "hormone replacement" treatment groups along with extirpation treatment groups in order to identify the function of a particular hormone?
3. Describe several ways in which drugs can be used to decrease or increase the effects of a hormone in the body.
4. What is a bioassay? How may beard growth be used as a bioassay?
Definition of a hormone
1. What is meant by the phrase that a hormone is an "intercellular signal"?
*2. What is the difference between an autocrine factor, a paracrine factor, an endocrine factor and an ectocrine factor [see text]?
3. What kind of cells can be a source of hormones?
4. What kind of cells can be a target for hormones?
5. How do hormones reach their target?
6. What distinguishes a hormone from a neurotransmitter?
7. What is meant by the phrase that "many hormones are systemic"?
8. What determines whether or not a particular cell in the body is a target for a systemic hormone?
9. What are 4 different classes of chemical structures of which most hormones are members?
10. Can a particular type of molecule be both a hormone and a neurotransmitter?
11. What may be 2 advantages of using a hormone for an intercellular chemical signal rather than a neurotransmitter?
12. What may be 2 disadvantages of using hormones rather than neurotransmitters for intercellular signalling?
13. Every hormone can be described as belonging to one of two general functional categories. What are they?
The Endocrine System
1. What is the difference between endocrine glands and exocrine glands?
2. What are two examples of tissues that contain endocrine cells which are not "clumped" together into an endocrine gland?
3. Where is the pineal gland located?
4. Why is the hypothalamus sometimes considered part of the endocrine system?
5. Where is the hypothalamus located?
6. Can the hypothalamus be divided into subnuclei?
7. Where is the pituitary located? What is the sella tursica?
8. What is the adenohypophysis?
9. What is the neurohypophysis?
10. Developmentally, where do cells of the adenohypophysis and the neurohypophysis originate from?
11. What is the portal system?
12. What is the primary portal plexus?
13. What is the secondary portal plexus?
14. What is the infundibulum or pituitary stalk?
15. What is the median eminence?
16. Where is the median eminence located?
17. What is a neurohormone?
18. Which neurohormones are produced by parvocellular neurons? Why?
19. Which neurohormones are produced by magnocellular neurons? Why?
20. What is a "tropic" hormone?
Features of Specific Hormones
First Order Neuroendocrine Arrangement:
1. What are two neurohormones that represent a first order arrangement?
Second Order Arrangement:
2. What hypothalamic releasing factors regulate the production and secretion of growth hormone, prolactin and beta-endorphin?
Third Order Arrangement:
3. What hypothalamic releasing factors and anterior pituitary tropic factors regulate the production and secretion of thyroid hormones, glucocorticoids, estrogens, progesterone, and androgens?
1. Where are the cell bodies located for the neurons that produce the neurohormones oxytocin and vasopressin (be specific)?
2. Where are the axon terminals located for the neurons that produce the neurohormones oxytocin and vasopressin?
3. What are two primary effects in the body of the neurohormone oxytocin?
4. What are two primary effects in the body of the neurohormone vasopressin?
5. Describe the suckling reflex.
6. What do we mean when we say the suckling reflex can be classically conditioned?
7. What effect does alcohol consumption have on vasopressin secretion, and what are its implications for micturition and hemorrhage?
8. What proteins are both a portion of the prohormones for oxytocin and vasopressin and also act as carrier proteins for oxytocin and vasopressin?
9. Why do oxytocin and vasopressin need a carrier protein?
*10. What is the basic chemical structure of oxytocin and vasopressin (e.g. protein, peptide, steroid, monoamine, lipid)?
11. Where are the axon terminals located for the neurons that produce the neurohormones that regulate the production and release of tropic hormones in the anterior pituitary?
12. How do hypothalamic releasing factors reach the anterior pituitary?
*13. What are two examples of basophils, and what hormones do they produce?
*14. What are two examples of acidophils, and what hormones do they produce?
*15. What are two examples of chromatophobes, and what hormones do they produce?
16. What is a primary effect of growth hormone?
17. What is a primary effect of prolactin?
18. What effect do dopamine antagonists (e.g. the antipsychotic drug—haloperidol) have on prolactin secretion? Why?
19. What is the proopiomelanocortin (POMC) protein?
20. How are ACTH and beta-endorphin related chemically?
21. What is a primary effect of beta-endorphin in the body?
22. Which hypothalamic releasing factors have an inhibitory effect on the release of anterior pituitary hormones?
23. Which hypothalamic releasing/inhibiting factor is not a peptide?
24. Where are the neuronal cell bodies located that produce CRH?
25. Where are the neuronal cell bodies located that produce GnRH?
26. What are 3 tropic hormones that are also effector hormones?
27. What is one hormone that is produced by the pancreas?
28. What is one hormone that is produced by the gut?
29. What is one hormone that is produced by the adrenal medulla?
30. What is one recently discovered hormone that is produced by fat cells?
31. What are two hormones that are produced by the adrenal cortex?
32. What is the principle glucocorticoid found in humans?
33. What is the principle estrogen found in human females?
34. What is the principle androgen found in human males?
*35. What cell structure in the ovary produces progesterone and what stimulates those cells to begin to produce progesterone?
*36. Describe the separate role of Sertoli cells and Leydig cells in the testes. Which are endocrine cells [donŐt forget fetal development]? Which is a target for LH and which is a target for FSH?
1. True or False. Most releasing factors are released in a pulsatile fashion.
2. What is hormonal negative feedback?
3. What role does hormonal negative feedback play in compensatory hypertrophy?
4. What happens to GnRH, LH and FSH levels if both testes are removed?
*5. What happens to GnRH, LH and FSH levels if one testis is removed?
6. What happens to GnRH, LH and FSH levels if someone takes high levels of androgens, e.g. anabolic steroids?
7. What effect would taking high levels of androgens have on spermatogenesis? Why?
8. What effect does sustained treatment (after 1 week or so) of a male with a GnRH agonist (drug that binds to GnRH receptors and produces the same effects as GnRH) have on LH and FSH secretion? Why?
9. What is receptor downregulation?
Biochemistry of Hormones
1. What is a gene?
2. Are there genes which code directly for proteins? for steroids? for thyroid hormone? for adrenaline?
*3. Compare the water solubility, ability to pass through cell membranes and ability to penetrate the blood brain barrier of proteins and peptides versus steroids and thyroid hormones?
*4. What is the blood brain barrier?
5. Why do steroids and thyroid hormones need carrier proteins?
6. Where are carrier proteins for steroids and thyroid hormones produced?
7. What are the carrier proteins for cortisol, testosterone, estradiol, progesterone, and thyroid hormones?
8. Why are receptors for protein and peptide hormones located on the outer surface of cells, whereas receptors for steroids and thyroid hormone located inside the cell?
9. Why are peptide hormones, but not steroid hormones, stored in vesicles?
10. What is the implication of vesicular storage of hormones in regards to rapid release of hormones into the blood stream?
11. What is a metabotropic receptor?
12. What is the basic building block for peptides and proteins (i.e. what class of molecules are linked together in a chain to form peptides and proteins?)
13. What is the common precursor (simple building material) for steroids? for thyroid hormones?
14. Why are steroid and thyroid hormone receptors called hormone dependent transcription factors?
15. What is a transcription factor?
16. What 2 functional domains do steroid receptors have?
17. What makes a liver cell different from a neuron?
18. What are the basic steps of protein synthesis as depicted in the diagram in the handout?
19. In which compartment (cytoplasm vs. nucleus) does transcription and translation take place?
20. What is a "free" hormone?
21. Where in the cell are unoccupied cortisol receptors (glucocorticoid receptors) located?
22. What is meant by "activation" of steroid receptors?
*23. What happens to glucocorticoid receptors after they become activated?
*24. What is a Hormone Response Element? What is a Glucocorticoid Response Element?
25. Why after stimulation of CRH neurons or GnRH neurons in the hypothalamus is there a considerable lag time in the onset of steroid hormone actions at target tissues?
Sex Determination and Differentiation
1. What is meant by "sexual dimorphism"?
2. What is sexual differentiation?
3. What are the components of the accessory sex organs?
4. What are the components of the external genitalia?
5. What determines whether an embryonic gonad develops into a testis or an ovary?
6. On what chromosome is the gene (SRY) that codes for the testis determination factor (TDF) located?
7. Can an individual have both a testis and an ovary? How?
8. What hormones do the embryonic testes produce?
9. What hormones do the embryonic ovaries produce?
10. What is an anlagen?
11. What are the Wolfian duct and the Mullerian duct?
12. What determines whether the Wolfian duct or the Mullerian duct continues to develop in an embryo?
13. What is Mullerian inhibitory hormone (MIH)?
14. What cell type in the testes produces MIH?
15. What cell type in the testes produces testosterone?
16. How can an individual have both a Wolfian duct and a Mullerian duct remain throughout development?
17. What hormone regulates the differentiation of the external genitalia?
18. What is 5-alpha-reductase?
19. What role does 5-alpha-reductase have in differentiation of the external genitalia?
20. What happens to human sexual differentiation if no gonadal hormones are present during fetal development?
21. What role does the Y chromosome play in determining male vs. female differentiation?
22. What is Propecia and why should it not be used by pregnant women?
Anomalous Mammalian Sexual Differentiation
1. What is the difference between a hermaphrodite and a pseudohermaphrodite? Which is more common?
2. What are the biological causes of the following anomalies, and what are some of the consequences of these anomalies on gonadal development, accessory sex organ development, external genitalia and secondary sex characteristics?
a. a defect in the SRY gene
b. testicular feminization mutation (TFM) or androgen insensivity syndrome
c. a defect in the production of MIH or its receptors
d. 5-alpha-reductase deficiency
e. congenital adrenal hyperplasia
f. Prenatal exposure to diethylstilbestrol (DES) or medroxyprogesterone acetate (MPA)
g. Turner syndrome (XO monosomy)
h. Klinefelter syndrome (XXY trisomy)
i. XYY trisomy
3. Why don't individuals with TFM have pubic hair, but have well developed breasts?
4. What is the cause of the adrenal hyperplasia in congenital adrenal hyperplasia?
5. What are guevedoces? What gender identity do most guevedoces express after puberty?
6. Why may a high proportion of XYY individuals end up in prison?
7. On what chromosome is the gene located for the androgen receptor?